I was not so aware of expiration dates for beauty products, but I think it is very important to pay attention to them, especially for skincare products. First, where can we find expiration dates? Usually, companies print either period after opening (PAO) or expiration date on the container. Expiration date is straightforward which means you need to toss out the product before the date. It usually reads ‘EXP**/**’ or ‘Best by**/**’.
As to PAO, you need to find “open jar” sign with a number followed by the letter M, which indicates the time period (in months) the product can be safely used after opening.
In the picture above, the first product can last 12 months upon opening while 24 months for the second one.
Every time I open a new container, I write the date on a sticker and attach it to the container, so I always know when I should throw out the product. I find it is very beneficial in some other ways. For example, if you have unusual breakouts/allergy reactions, you can check the stickers to pinpoint the product that causes the problem.
As to makeup items, I only use this method to liquid and cream products because powders do last quite a long time. Also, since I have sensitive eyes, I do track the date of eyeliners.
I am definitely not being comprehensive, but I really want to share my opinions on it. Thanks for reading!